[en] This issue is the collection of 1135 paper presented at the title conference. The 25 of the presented papers are indexed individually. (J.P.N.)

[en] We developed a nondestructive measurement method of defect shapes (single crack or branched crack and inclination angle) existing on the surface of steel flat plate of uniform thickness by ultrasonic waves incident from the back surface. The change in reflection intensity (C scan image) due to the probe position was measured by the normal beam technique by single transducer operation with immersion testing. In this study, the defect shape is evaluated from the characteristics of interference fringes of reflected intensity. Asymmetrically branched defects and symmetrically branched defects are identified using the deviation from symmetry of interference fringes of reflection intensity and, the change rate of reflection intensity with probe position, indicating their effectiveness. (author)

[en] A general-purpose three-dimensional thermohydraulics numerical simulation code SPLICE was developed at Japan Atomic Energy Agency and designed to deal with gas-liquid-solid consolidated incompressible viscous flows with a phase change process in various laser applications, such as welding, coating, cutting, etc. The result obtained from metal powder laser additive manufacturing simulations is very encouraging in the sense that the SPLICE code would be used as one of efficient tools to provide the laser irradiation conditions. (author)

[en] For seismic studies of piping systems during strong seismic ground motion, there are only a few experiments and analyses to examine the dynamic behaviors of pipe support structures in the condition of their elasto-plastic deformation although many multifarious seismic research studies for pipes have been done. Therefore, the realistic seismic response of piping systems during strong motion should be investigated for the condition that the both pipes and pipe support structures simultaneously extend to elasto-plastic deformation. In this study, a three-dimensional piping system with frame-type supports was three-dimensionally excited using strong motion and the vibration response was researched. The elasto-plastic response of the piping system due to the plastic deformation of both pipe and support occurred during the maximum strong excitation and the response reduction caused by the plastic effect was observed. (author)

[en] Thermal fatigue cracking may initiate at a tee pipe where high and low temperature fluids flow in. The mixing flow causes temperature fluctuation near the pipe wall and may result in fatigue crack initiation. In this study, flow pattern at the mixing tee pipe was investigated by experiments in order to prevent the thermal fatigue. Visualization of flow was conducted by a test section of transparent acrylic resin and a tracer method. This test section is consisted of a horizontal main pipe with an inner diameter of 150 mm and a vertical branch pipe with an inner diameter of 50 mm. Flow in the main pipe penetrated into the branch pipe. The penetration patterns were categorized by the momentum ration for the flows in the main and branch pipes. The maximum penetration depth was measured from the movement of tracer particles. Relationship between the maximum penetration depth and the momentum ration was investigated. (author)

[en] In nuclear power plants, the structural components that are in contact with coolant are susceptible to thermal loads due to the change in the fluid temperature. If the heating and cooling processes are repeated, the structure will endure thermal fatigue that may lead to failure. Thermal stratification is one of the main loads that can lead to high cycle thermal fatigue damage. The Japan Society of Mechanical Engineers (JSME) has published the evaluation guideline for high cycle thermal fatigue. It treats branch pipe due to thermal stratification, however, it does not contain an analysis method for stress evaluation. This study was aimed at evaluating the thermal stress generation under local temperature fluctuation by thermal stratification at an elbow pipe in a nuclear power plant. A Finite Element Analyses was adopted to study the thermal stress characteristics and their mechanics. In addition, the results were compared with an analytical approach based on a frequency response function. (author)

[en] Pipe wall thinning is an important issue for aging management of nuclear and fossil power plants. The Japan Society of Mechanical Engineers (JSME) published a guideline on pipe wall thinning management in 2005 and management codes in 2006, which is based on inspection using UT. In JSME, research committee for the improvement of pipe wall thinning management has been held since 2008, where state of the arts technical knowledge was investigated. In this committee, research for new technical knowledge for the mechanisms of wall thinning, evaluation methods, new inspection methods etc. Regarding the evaluation methods, how it is reflected to the management codes is considered. Risk based management and criteria for local wall thinning are also investigated. (author)

[en] We examine the effectiveness of the damping device that suppresses sliding motion and rocking motion of a free-standing large cylindrical structure called cask. For suppressing the sliding motion of the cask, our previous research developed a sliding motion suppression device consisted by highly viscous liquid and coaxial circular cylinders. This sliding motion suppression device is very effective for sliding motion suppression and is thought to be effective also for rocking motion suppression. In this study, the damping effects for rocking motion are experimentally measured using a fundamental test model. And sliding motion and rocking motion of cask excited by base excitation for various damping coefficients were investigated analytically. The damping effect works when the highly viscous liquid moves through the gap between the coaxial cylinders or the gap at the cylinder bottom. Then the sliding motion and rocking motion are suppressed. It is found that increase in fluid viscosity or decrease in bottom gap brings high damping coefficients. And high damping coefficients for sliding motion and rocking motion are effective for sliding motion and rocking motion suppression, respectively, when input acceleration is sinusoidal wave. And the damping device is also effective for sliding motion and rocking motion suppression even when input acceleration is seismic excitation. (author)

[en] Thoriated tungsten alloy (ThO₂-W) has been used as cathode material in discharge lamp and for TIG welding rod because of its excellent thermoelectric emission properties. However, ThO₂ is one of radioactive substances, therefore development of thoria free tungsten is desired. In this study, hafnium carbide (HfC) was used as an alternate material of ThO₂. The material used, HfC-W alloys was produced with spark plasma sintering (SPS) and tensile strength of the alloy at elevated temperature was evaluated. Tensile strength of HfC-W sintered by SPS decreased with increasing testing temperature. Tensile strengths at 1300 and 1500degC in HfC-W sintered by SPS were lower that in the same alloy but sintered by conventional electrical sintering technique. According to microstructure observation by SEM-EDS in the materials used, coarse aggregate of HfC were observed in HfC-W sintered by SPS, while small HfC particles were distributed in the matrix for HfC-W sintered by electrical sintering. It is considered that difference in dispersion state of HfC particles possibly affects tensile strength of the materials used. (author)

[en] To reduce the human errors is important for plant engineers. Therefore, we have improved the quality of seismic design and analysis of power plants. The purpose of this paper is to introduce the tool development for quality improvement of seismic design and analysis. We focused on the transcription error which is one of human errors in the design documents and the inputs of seismic analysis. We classified the transcription work into three types to clarify the automatable transcription patterns and the non-automatable transcription patterns. On the basis of the classification, we have developed a transcription errors check tool program as one of solutions for reducing the human errors occurring in the non-automatable transcription patterns. This tool is designed using the database which is based on possible error pattern, and the tool can make it easier to recognize the transcription errors in the design documents and the inputs of seismic analysis. (author)